HOME > Notice of GPS week number rollover on GPS Navigator / Sensor
To All Customers:
We greatly appreciate your use of our products.
This is to inform you of the “GPS week number rollover” problem and how it affects our GPS Navigator / Sensor.
The GPS system calculates time by counting the number of weeks up to a maximum of 1,023 weeks. After week 1,023, the week number count is reset to zero. This is called “GPS week number rollover”.
The GPS week number rollover occurs every 1,024 weeks - about once every 19.6 years. Therefore, when 19.6 years has passed from the reference date in the systems, the clock time incorporated in GPS sensors and navigators will be reset, causing as a result errors in display or output of date, or unstable occurrence in positioning operation.
When GPS week number rollover occurs, our GPS Navigator / Sensor may cause the following problems:
When this rollover has occurred, please switch on the equipment twice to recover the normal positioning operation. After recovery of the operation, the date will remain as it is in 19.6 years ago, but time and positioning operation will function normally.
We regret any inconvenience this may cause you, but appreciate your kind understanding in this matter.
Please refer to the tables below for countermeasures for each type of equipment.
It is possible to postpone the occurrence of rollover to the year of 2028 by upgrading of software, but it may not be possible to upgrade software, even if charge is paid, as the needed ROM software may not be available on all models. In such cases, replacement of equipment will be provided with charge. Please contact our distributors / dealers where you have purchased or our marine sales department for details on the equipment subject “upgrading of software version”. We appreciate your kind understanding that the cost shall be born by you for either case of the countermeasure above mentioned.